excessive weight - ramifications

[ericos]

Hi all. I've been reading for about a month, but this is my first post.

I'm wondering what the ramifications are for excessive weight on the Phantom 2. The manual says 1300 grams or less. I weighed mine, and it came in at 1399 grams. I have a go pro, gopro battery, dji video transmitter and cloverleaf antenna, zenmuse gimbal, mini osd, a separate gps tracker, and a small mounting plate I made.

Obviously flight time will be reduced, but am I introducing any negative flight characteristics?

I can't think of much I can cut out. I looked at taking out the gopro battery (53 grams) as the camera lights up from the phantom battery but it looks like it needs its own internal battery to actually function.

gps tracker with battery and sim card is light at 53 grams. This gives me peace of mind after losing my first phantom 1 (stock no camera or anything)

back plate is light plastic (25 grams) and gives me a convenient place to mount the tracker.

The fat cable coming off the dji transmitter seems more heavy than it needs to be. I was toying with the idea of removing the outer casing as the internal wires are much smaller, but that said, I estimate I'd only be saving about 40 grams or less.

Not sure where I can trim the fat, but wondering if it really matters.

Thanks!

 

[thongbong]

It may cause the frame underneath the motors to crack if you have too much weight. Happened to my P1. Happy flying!

 

[wincrasher]

reducing weight and impoving aerodynamics will always lead to better flight performance and times.

one other thing to consider too is center of gravity, or how your load is balanced?

also, have you noticed if your plate is creating - for lack of a better term - a wing effect? I'd be concerned with that flat plate as opposed to maybe some kind of rods to hold your tracker.

 

[ianwood]

I don't know the exact implications of excessive weight but in the best case, your phantom will move more slowly, take longer to stabilize coming out of maneuvers and your motors will need to work harder decreasing run time. On the more serious side of things, I would guess the risk of stalling increases as the props get closer to their limits. You can recover from a stall if you're high enough but otherwise, it's not good.

When I look at your bottom plate and tracker box, it looks bad to me for several reasons:

- Your tracker is right next to your compass. The reason the compass is alone on the leg of the phantom is that it is tremendously sensitive to interference from ferrous (metal) objects, EMI, etc. You may now have a means of dealing with a fly away but you've also increased the odds of one happening.

- You've added weight far away from the CoG. Fortunately, it is down low which brings your CoG down but the further away you get from the CoG, the stronger the influence (moment and arm: a weight at the end of a long stick is much harder to move than one in your hand). Your phantom will have to work harder to pitch itself in the direction you want to go because it has to shift additional weight positioned at the bottom of your landing gear.

- That plate is going to effect aerodynamics. It will be partially in the prop wash, meaning your phantom is somewhat thrusting against itself. When traveling at speed, it will act like a speed brake pushing the opposite side down when it's trying to lean in the direction of travel.

 

[ericos]

Thanks for the advice. That all makes good sense. I hadn't notice any problem with prop wash (or whatever its called) in relation to the mounting plate and poor flight characteristics, but I'm fairly new to flying this thing so not sure I would notice it if there was. Guess I'll ditch the plate and look into strapping it to one of the legs (being mindful of compass and receiver antennas). That'll be 25 grams I lose (at least 75 more to go!)